What's inside
As an Amazon Associate I earn from qualifying purchases. This post may contain affiliate links at no extra cost to you.
What we cover
What the job demands
Installing masonry screws in concrete block is a drilling-and-fastening job, not a reason to buy the biggest hammer drill on the shelf. The drill has to make a clean pilot hole at the diameter and depth specified for the screw, then drive the fastener without stripping its head or spinning out the hole. A compact 18V or 20V cordless hammer drill is enough for occasional brackets, conduit straps, and shelves. Battery capacity, a side handle, and control at low speed matter more than a headline torque figure.
Block varies. A hole through the relatively soft face shell is easier than one that hits a hard aggregate or a web. Hollow block can also crack or crumble if you hammer aggressively or use a hole that is too large. Follow the screw maker’s instructions for bit diameter, embedment, edge distance, and whether the fastener is suitable for hollow or solid masonry. A masonry screw that works well in solid concrete may not be the right choice for a thin block face shell.
As an Amazon Associate we earn from qualifying purchases at no extra cost to you.
What to buy
For a homeowner drilling a few holes at a time, a standard cordless hammer drill with a three-jaw chuck is the practical choice. It accepts common round-shank masonry bits and can also handle wood and metal work with hammer mode turned off. Compare 18V cordless hammer drill kits by checking whether the kit includes a battery and charger; bare tools are only a bargain if you already own compatible batteries.
For frequent masonry work or larger holes, consider a cordless rotary hammer with an SDS-Plus chuck. Its bit shank locks in rather than relying on a three-jaw grip, and its hammering action is more efficient in masonry. The trade-off is that it is less versatile for ordinary drilling unless it has a selectable rotation-only mode and you have suitable bits. For a handful of small screw pilots in block, it is usually more tool than you need.
Hammer drill or rotary hammer?
| Tool | Best fit | Trade-off |
|---|---|---|
| Compact 18V/20V hammer drill | Occasional screw pilot holes, mixed household drilling | Slower in hard aggregate; needs a sharp, suitable masonry bit |
| Heavy-duty hammer drill | More frequent holes or larger diameters with standard bits | Heavier and often pricier; still less efficient than SDS-Plus for sustained masonry work |
| Cordless SDS-Plus rotary hammer | Repeated masonry holes or tougher concrete and block | More specialized; SDS bits and compatible accessories are required |
Do not choose by advertised torque alone. Torque figures are measured differently across brands and say little about how quickly a tool will drill a small pilot hole. Look for a two-speed gearbox, a hammer-mode selector, a clutch for driving screws, and a side handle on larger tools. If the job involves overhead drilling or many holes in a row, tool weight and vibration become especially noticeable.
Bits and fasteners matter
Use a carbide-tipped masonry bit in good condition, sized exactly as the masonry screw manufacturer specifies. Do not assume the screw diameter is the bit diameter: a nominal 1/4-inch screw, for example, may call for a different pilot size. The product instructions take priority. A worn bit can wander, run hot, and leave an oversized or ragged hole that will not hold the screw properly.
A conventional hammer drill uses round-shank bits held in its chuck. SDS-Plus tools require SDS-Plus bits, though some rotary hammers accept a separate chuck adapter for round-shank accessories. An adapter can add wobble and is not a substitute for the right bit during demanding masonry drilling. For a standard hammer drill, compare carbide-tipped round-shank masonry bits; buy the size you need rather than a large assortment of low-quality bits.
Drilling and driving without damaging the hole
Mark the hole and check the block for edges, mortar joints, and hidden services. Keep the screw’s required edge distance; drilling too close to an edge can split the face shell. Hold the drill square to the wall, start slowly to keep the bit from skating, then use hammer mode at a steady pace. Let the bit cut rather than forcing the tool. If it stops advancing, withdraw it periodically to clear dust. Excessive pressure can overheat the bit or make a weak shell break out.
Drill to the specified depth, allowing room for dust at the bottom. A depth stop or tape mark helps; do not count on the screw to clear debris from a blind hole. Brush or blow out the hole as directed by the fastener maker. Dust left inside can prevent full seating and reduce holding performance. Wear eye protection, and use respiratory protection or dust extraction when drilling produces airborne masonry dust.
For driving, switch out of hammer mode. Use the drill’s low-speed setting and clutch if the screw maker permits a clutch-driven installation. Stop when the head seats; driving on after that can strip the recess, break the screw, or spin the threads in the block. If the screw binds early, back it out and inspect the hole rather than leaning harder on the trigger. A cordless impact driver can drive compatible screws quickly, but its impacts make it easier to overdrive or damage a marginal hole. For a few fasteners, a drill’s slower control is often the safer choice.
Common failures and when to spend more
If a screw spins without tightening, the pilot hole may be oversized, damaged, or in weak material. Do not keep driving it; move to a new location that meets the fastener’s spacing rules or use an anchor system rated for the block and load. If the hole crumbles at the opening, reduce pressure, check bit condition and placement, and avoid hammer mode if the fastener instructions and material allow a rotation-only pilot. A hole that wanders is often a sign of starting too fast or using a dull bit.
Spend more for an SDS-Plus rotary hammer if you routinely drill many holes, work in hard masonry, or need larger diameters. If you are installing a small number of masonry screws in ordinary block, a basic cordless hammer drill and a quality bit are usually sufficient. A corded drill is also a reasonable low-cost option if mobility is unimportant, but it does not remove the need for the correct bit, hole size, and careful driving.